William e



' (No Model.)

W. E. PRALL.

COOKING STOVE AND RANGE.

Patented May 1, 1888.

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NITED STATES PATENT rica.

WILLIAM E. .PRALIQOF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE NATIONAL HEATING COMPANY, OF

NEW YORK, N. Y.

SPECIFICATION forming part of Letters Patent No. 382.24 dated May 1, less.

Application filed October 11, 1887. Serial No. 252,087. No model.)

- Washington, in the District of Columbia, have invented certain new and useful Improvements in Cooking Stoves and Ranges, of which the following is a specification.

My invention relates to an improvement in steam or hot-water cooking ranges.

I have found from experiments that in order to get the required temperature for roasting and baking it became necessary to have a very high pressure, as the temperature and pressure increase and diminish in corresponding ratios when water or steam is employed as the medium of transmission, and in view of that established fact I have endeavored in the con struction of this apparatus the accomplishing of the highest results without incurring danger from overpressure.

Figure 1 of the accompanying drawings shows in perspective one of my improved ovens. Fig. 2 is an end view of a series of ovens arranged in connection with each other and with the necessary supply-pipes. Fig. 3 represents one of the cooking'pans suit-able for such an oven. Fig. 4. is a lining for an oven, provided with lugs or ways on which to slide partitions for dividing the ovens into sections for baking bread, pastry, 850. Fig. 5 is a front elevation of a range ora stove provided with three bakingovens and two warmingovens and two boilingtanks, also a grate for broiling purposes.

In the practical construction of my invention the ovens are made of wrought-iron pipe of a suitable size, about oneinch in diameter, formed into a coil of an oblong shape and of the desired depth and diameter. The pipes may be wound close together, so as to touch each other, or a considerable distance may be left between them. The lower portion of the cylinder thus formed may be filled in between the coils with some material (B, Fig.1) which is a good conductor of heat, which may consist of separate pieces or solid bands, so as to form a continuous heating-surface, the same as if it were one solid iron piece, (or, if desired, the filling may extend around the cylinder or oven, so as to form a continuous smooth heat ing-surface therein.) The upper part of the oven thus constructed should be left with the pipes exposed from the inner side, as in that condition the largest amount of heating-surface would be exposed to the interior of the oven. The outer surface of the coil should be covered withsome material (0, Fig. 1) known as a non-conductor, to prevent the radiationv of heat in that direction. This result may be accomplished by a covering of mineral wool, 50 asbestus, hair-felt, or a plaster of composition.

As there are so many kinds of material adapted for this purpose, I do not confine myself to any one of them or to the manner of applying them. It will readily be seen that by constructing an oven in this manner the greatest amount of heatingsurface will be obtained in the simplest manner, and that a great pressure may be carried without any danger, as wrought iron pipes of so small a diameter will easily withstand a pressure of several hundred pounds tothe square inch, while if the ovens were constructed of cast iron cylinders of the required diameter for an oven and a pressure approximating that which could be 7 5 carried with perfect safety in small wrought iron tubes were created therein there would be great danger of their bursting, even if constructed of great weight and thickness; be-

sides there would be great difficulty in making 8c tight joints between the cylinders of such a character.

E, Fig. 3, represents a removable cookingpan suitable for an oven formed as described; and D, Fig. 4, a lining for an oven provided wit-h lugs or ways on which to slide partitionplates for dividing theovcns into sections for baking bread, pastry, 85c.

In Fig. 2 I have shown an arrangement of three ovens made as herein described, provided with water'supply pipes a, a, a, and a and. water-return pipes b, b, b", and b",and in Fig.

4. a range or stove of a form or construction adapted to receive such an arrangement of ovens. Thelocation of the ovens is shown at 5 F, F, and F, and the lower two are provided with doors having glass panels f and f and the upper oven, F, may also be provided with a similar door, if necessary. The pipes a, a and a. supply the ovens with the necessary heating medium, and the pipes 1/,12", and I) return the same. The glass doors serve for the admission of light to the oven, whereby the contents thereof may be inspected without opening the doors, and thus avoid the reduction of temperature that would result from so doing,which would arrest the process of cooking for a time and greatly injure some kinds of food. This range is also provided with warming-ovens G and G (having doors 9 and g) which are not provided with coils for heating or baking, but in which articles of food may be warmed by radiated heat only; also with upright boiler-tanks m x, which may be supplied with the heating medium from pipe I), as shown in dotted lines. These tanks may i be made by first coiling the pipe in the desired shown in Fig. 1.

form and casting the metal around the coil thus formed, or by filling in between the coils, as'hereinstated with reference to the oven The pipes which form the oven may be made square in cross-section, if desired, and it is evident that many different forms maybe adopted without departing from the spirit of my invention.

Having thus described my invention, what I claim, and desire to secure by Letters Patcut, is-

1. An oven for cooking stoves or ranges, composed of a coil of pipe adapted to the circulation of steam or hot water, the spaces be tween the coils being filled in with a heat-conducting material, substantially as shown and described.

2. An oven for cooking' stoves or ranges, composed of pipes, the space between the pipes being filled in with a heat-condueting material, and incombination with a covering of asbestus or equivalent substance, substantially as shown and described.

' 3. An oven for cooking stoves or ranges, composed of steam or hot-water circulating pipes, the space between the pipes in thelower half of the oven being filled in with heatconducting material, substantially as shown and described.

4. An oven for cooking stoves or ranges, composed of steam or hot-water circulating pipes, the space between the pipes in the lower half of the oven being filledin with heat-conducting material, in combination with a covering of asbestus or equivalent substance, substantially as shown and described.

5. An oven for cooking stoves or ranges, composed of steam or hot-water circulating pipes, constructed substantially as shown-and described, in combination with alining, D, provided with lugs or ways, substantially'as and for the purposes set forth.

6. The combination, with a cooking stove or range, of an oven or ovens consisting of coils of pipe adapted to circulate steam or hot water, the space between the coils being filled with heat-conducting material, and the ovens surrounded with non-heat-conducting material and provided with pipes at and b, substantially as shown and described.

7. The combination, with the frame of a cooking stove or range, of a series of pipe ovens, arranged together as shown, each being surrounded with non-heat-conducting material and opening on or through the face-plate of a stove or range, warming-ovens, as G and G, and boiler-tanks X X, substantially as shown and described.

Signed atthe city ofNew York, in the county of New York and State of New York, this 5th day of October, 1887.

WWW. E. PRALL. Vitnesses:

DANIEL E. DELAVAN, FRANK O. F. KNAAK.

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